Sliding screw adjustable wrist pin



Feb. 1 1938. E. E. FRANCIS SLIDINGv SCREW ADJUSTABLE WRIST PIN Filed Feb. 5, 1937 arr/mau S,

w w 4m #42 q u 3 34mm m z w A n W n 4 NF. 7 o 0 a 8 a k y M a w w 1 J d 5 1; T Mm A. l NN 4 z (W m. i m m v 4 m A Patented Feb. 1, 1938 onirso srarss PATENT cr tics 1 Claim.

This invention relates to sliding screw adjustable wrist pin.

This device is for any type of crank, on an oil well pumping unit, or a standard drilling rig.

An object of the invention is the construction of a simple and efiicient device, whereby time and labor will be saved, inasmuch as one person can easily adjust the device to a fraction of an inch, in a few minutes. A further object of the invention is the production of a device whereby a person can quickly and easily change the stroke of the pump from one-thirty-second of an inch to three feet. Further, it is to be understood that with my device the adjustment can be accomplished without removing the pitman.

A still further object of the invention is the construction of a device with a suitable scale, so that accurate adjustment can be accomplished; in other words, the crank is calibrated from the center of the band shaft to the center of the wrist pin, when the radius of the crank is known at all times.

With the foregoing and other objects in view, my invention comprises certain novel constructions, combinations and arrangements of parts as will be hereinafter fully described, illustrated in the accompanying drawing and more particularly pointed out in the appended claim.

In the drawing:

Figure 1 is a view in front elevation of a device constructed in accordance with the present invention.

Figure 2 is a vertical sectional view, taken on line 22, Figure 1, and looking in the direction of the arrows.

Figure 3 is a view in rear elevation.

Figure 4 is a central sectional View taken on line 4 i, Figure 2, and looking in the direction of the arrows.

Figure 5 is a horizontal sectional view taken on line 5-5, Figure 1, and looking in the direction of the arrows.

Figure 6 is an enlarged fragmentary sectional view of the lower part of the device.

Figure '7 is an enlarged fragmentary View of a portion of the front of the device, showing particularly the scale, for calculating the adjustment desired.

50 Referring to the drawing by numerals, I designates an inverted substantially U-shape frame having a closed back (Fig. 3), and is also closed at its bottom by a detachable end section 2. Extending from within the top portion of frame I is operating shaft 3. The end section 2 is provided with two dove-tail tenons 4 which slide into similarly constructed grooves 5 formed in the lower ends of the sides of frame i. To positively lock the end section 2 in position I employ two long fastening bolts 6 that extend up through 5 tenons 4 and into the sides of the frame, as clearly shown in Fig. 4.

A side recess 7 is formed in the top portion of the frame 4, and the sides of the frame are provided in their inner faces with centrally- 10 located elongated grooves 8. In these grooves 8 are adjustable bearing strips 9, which strips 9 bear at one end against shoulders 8a formed in grooves 8. The strips 9 are engaged by the inner ends of adjusting bolts Ill, which bolts It! 15 extend through the sides of the. frame, Fig. 4. Shaft H extends through end section 2 and the central portion of frame I, and is provided upon its inner end, within recess 1, with a collar or nut 42; this nut or collar is fixedly secured upon. the inner end of shaft II by any suitable fastening means 13, such as a screw or cotter pin. Positioned upon shaft ll within recess 1 is also a roller bearing Hi; this bearing is between a portion of frame I and nut l2. The shaft H is screw threaded a greater portion of its length, and is provided on its outer end with a collar or nut I5; this nut I5 is secured in place by any suitable fastening means It, such as a screw or cotter pin. A roller bearing I! is placed upon 30 shaft II between end section 2 and nut 16. These roller bearings M and I! produce an easily operated device.

A sliding block I8 is positioned between the sides of frame 5, and extending from opposite 35 sides of the block are narrow extensions [9 which fit into the centrally-located elongated grooves 8. These extensions l9 bear against the strips 9. Therefore, by means of bolts ID the strips 9 can always be made to nicely engage the 40 extensions IQ of block I8. Block i8 is provided with an outwardly-extending integral wrist pin 20. The block 18 is mounted upon the threaded portion of shaft It so that by rotating said shaft the block, with its wrist pin, will be adjusted longitudinally of the frame I.

I preferably form a suitable indicator 2! on block I8, and a scale 22 on the side portion of frame I. This scale is for a three feet adjustment, and by rotating nut I5 shaft M will be rotated, whereupon the operator can obtain an adjustment of from a fraction of an inch to three feet. It is also to be understood that it is easy to make the adjustment without removing the pitman.

I have found that the simple and peculiar arrangements of the elements of my device, produce an eflicient structure, whereby the desired adjustment can be easily obtained merely by the operator grasping the nut I5 and rotating the shaft, bearing in mind the scale on the side, whereby he will be able to readily determine the exact amount of adjustment obtained.

While I have described the preferred embodiment of my invention and illustrated the same in the accompanying drawing, certain minor changes or alterations may appear to one skilled in the art to which this invention relates during the extensive manufacture of the same, and I therefore reserve the right to make such changes or alterations as shall fairly fall within the scope of the appended claim.

What I claim is: 7

In a device of the class described, the combinatlon of an inverted substantially U-shape' frame including spaced side portions, said side portions provided with elongated grooves on their .inner faces, said sideportions provided in their outer ends with dove-tail groovesan end section provided withdove-tail tenons, said tenons in said dove-tail grooves, long fastening bolts extending through portions of said end section and through said dove-tail tenons and into the side portions of said frame, said frame provided in its side with a recess, said recess being formed in said frame ing on the outer portion of said shaft and. against 5 the outer face of said end section, a nut fastened to the outer end of said shaft and against the last-mentioned roller bearing, said frame provided in its side portions with registering elongated grooves, bearing strips in said elongated grooves, adjusting screws extending through the side portions of said frame and engaging said bearing strips, a block provided with a wrist pin adjustably mounted on said rotatable shaft between the side portions of the frame, and i said block provided with extensions at its.:sides engaging said bearing strips within said elongated grooves.

ELDON E. FRANCIS. 

